Knife block for cut pile tufting machine

ABSTRACT

A knife block for a tufting machine having provision for securely retaining a pair of aligned cutting knives therein and having spaced lateral slots therein permitting a clamping bracket to engage one of the edges of each knife at spaced points. Also, provision is made for easily aligning and securing the block to an oscillating knife bar of a tufting machine by a structure which includes a cylindrical shaft connected to the block and having a slot positioned in the end thereof at a predetermined angle, an opening in the bar for receiving the shaft, and a key secured to the bar and adapted to enter the slot in the cylindrical shaft to maintain a predetermined alignment.

United States Patent [72] Inventor James T. Cobble Dalton, G8. Appl. No.45,693

Attorney-Parrott, Bell, Seltzer, Park & Gibson [22] Filed June 12,1970[45] Patented Sept. 14, 197] Assignee B 8: J Machinery Co. Inc.

Dalton, Ga.

[54] KNIFE BLOCK FOR CUT PILE TUFllNG MACHINE and a key secured to thebar and adapted to enter the slot in the cylindrical shaft to maintain apredetermined alignment.

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PATENTEU SEPI 4191:

JAMES T. COBBLE;

INVENTOR.

ATT( )RNEYS KNIFE BLOCK FOR CUT PILE TUFTING MACHINE The presentinvention relates to a tufting machine for forming cut pile fabric, andmore particularly to the means for mounting the cutting knives in atufting machine.

In the tufting industry, many varied machines have been developed forcarrying a yarn through a backing fabric to form a plurality of tuftingloops, and for severing the loops to form the cut pile. A machine ofthis type is disclosed and described in my copending application, Ser.No. 26,603, filed Apr. 8, I970, and generally includes a plurality ofneedles for carrying the yarn strands through the backing, a cooperatinglooper associated with each needle for engaging and retaining the formedyarn loops, and a knife mounted on an oscillating mounting bar forsevering the yarn loops retained on the looper.

In tufting machines of the above-described type, it is conventional forthe knife to be retained and held in a knife block, which in turn iscarried by the oscillating knife bar such that the knife is reciprocatedacross the looper with a scissorlike cutting action. Typically, theknife block comprises a body member which includes a pair of side edgeportions and a connecting web, with a pair of opposed grooves formed inthe side edge portions to receive the knife. To retain the knife inproper position, a bore extends through the length of the connection webfor receiving a threaded member such that the threaded membercommunicates with one of the grooves and is thereby able to engage theedge of the knife. It has been found however, that the above lockingstructure not only severely weakens the web, but also the single pointof engagement with the knife is often insufficient to properly retainthe knife during long periods of use.

The prior tufting machines have also experienced difficulty inestablishing and maintaining proper alignment between the knife blockand knife bar. This can cause serious problems since the angularalignment between the knife and looper must be closely maintained toassure proper cutting action.

It is accordingly an object of the present invention to provide animproved mounting structure for the cutting knives in a tufting machinewhich is not subject to loosening or misalignment during prolonged use.

It is another object of this invention to provide a block for mountingone or more cutting knives in a tufting machine wherein the edge of eachknife is securely engaged or locked at more than one point along itslength.

It is a further object of this invention to provide means for easilyestablishing the proper alignment between a knife block and anoscillating knife bar in a tufting machine, and for maintaining thisalignment under the stress and vibration encountered during long periodsof use.

These and other objects and advantages of the present invention areachieved in the embodiment illustrated herein by the provision of aknife block which comprises a body member having side edge portions anda connecting web, and a pair of opposed grooves extending into the sideedge portions for receiving and mounting the knife. A pair of spacedslots extend laterally into one of the side edge portions and intocommunication with the associated groove, and a clamping bracketincluding a pair of spaced-apart legs is positioned such that the legsenter the slots to engage and lock the knife at spaced points. Athreaded member is employed to attach the bracket to the block and totranslate the legs into the slots such that they firmly engage theknife.

The knife block is aligned and secured to the oscillating knife bar by aconnecting structure which comprises a cylindrical shaft extending fromthe knife block and which includes a transverse slot positioned at apredetermined angle in the remote free end thereof. A cylindricalopening extends through the bar and is adapted to closely receive thecylindrical shaft of the block. A channel is positioned in the bar at apredetermined angle and which communicates with the cylindrical opening,and a key is adapted to be received in the channel and shaft transverseslot for maintaining the shaft in the desired angular relationship withrespect to the bar.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds when taken in connectionwith the accompanying drawings, in which FIG. 1 is a fragmentaryperspective view, partly sectioned, of a cutting mechanism in a cut piletufting machine which embodies the present invention;

FIG. 2 is an exploded perspective view of the knife block and lockingkey of the present invention;

FIG. 3 is a fragmentary side elevational view of the knife block and aretained knife;

FIG. 4 is a fragmentary end view of the knife block illustrating theangular disposition of the transverse slot at the free end of themounting shaft.

Referring to the drawings, FIG. 1 illustrates a yarn-cutting mechanismembodying the features of the present invention andiutilized in aconventional multiple needle cut pile tufting machine. Further detailsof a typical machine of this type may be obtained by reference to myaforementioned copending application. Generally however, the machineincludes a plurality of reciprocating needles 10, each of which carriesa yarn 11 through a backing fabric (not shown) to form a plurality oftufting loops, a plurality of loopers 12 secured to a looper head 14such that each looper is operatively associated with one of the needlesto engage and retain the tufting yarn loops, and a cutting knife 16operatively associated with each looper to sever the yarn loops. Theknives 16 are mounted for oscillatory movement in relation to theloopers, and are carried by a knife block 20, which in turn is mountedon an oscillating knife bar 22. As will become apparent from thefollowing description, a plurality of blocks 20 are mounted on the bar22 in a predetermined angular relationship with respect to the bar suchthat each knife will properly engage the associated looper l2 and severthe yarn with a scissorslike oscillating movement.

The knife block 20 comprise a generally rectangular unitary body memberhaving an I-shaped cross-sectional configuration, and which includesfirst and second side edge portions 24 and 26 respectively, and acentral connecting web 28. The central web 28 defines a pair ofoppositely directed planar faces 30 and 31 which are bounded by the sideedge portions 24 and 26, and with the side edge portions extendingtransversely beyond each of the faces. For the reason set forthhereinafter, the first side edge portion 24 has a somewhat greaterlateral dimension than does the second side edge portion 26.

The juncture between the web faces 30 and 31, and the two side edgeportions is in each case undercut along a line flush with the associatedface to define a pair of longitudinally extending opposed grooves 32,32' and 34, 34' for receiving a pair of the knives 16. To secure theknives in the opposed grooves, a pair of spaced-apart slots 36 and 37are provided which extend laterally into the first side edge portion 24and into communication with the grooves 32 and 34 (note FIG. 3), and alaterally extending threaded bore 38 is positioned in the side edgeportion intermediate the two slots. Clamping means for engaging theedges of the knives at spaced points include a U-shaped bracket 40comprising a pair of spaced-apart legs 42 and 43 which are adapted toenter the lateral slots 36 and 37 respectively, and an intermediatesegment 44 having an aperture 46 therethrough. An externally threadedcapscrew 50 extends freely through the aperture 46 and into threadedengagement with the bore 38 to thereby attach the bracket to the block20 and provide means for translating the legs 42, 43 into the slots 36,37 such that the legs will engage the two knives positioned in theopposed grooves at two longitudinally spaced positions. By thisarrangement, a secure, yet easily released mounting for the knives isprovided.

It will be noted from FIG. 3 that the bore 38 extends substantially thefull lateral length of the first side edge portion 24, but is somewhatless than the lateral extent of the slots 36 and 37. Thus the bore 38terminates short of the web 28, and this permits the diameter of thecapscrew to be greater than the thickness of the web. Also, the web willnot be weakened by the presence of a bore. While the above configurationis somewhat preferred since a stronger capscrew may be employed, it willbe apparent that by proper selection of the capscrew diameter, and webthickness, the bore 38 could be extended laterally into the web.

The structure for connecting the knife block 20 to the oscillating bar22 in a predetermined angular relationship includes a laterallyextending cylindrical shaft 54 which is connected to the second sideedge portion 26 adjacent the lower end of the block 20 and opposite theslots 36 and 37. The shaft 54 terminates in a remote free end 56 andincludes a transverse slot 58 extending a short distance thereinto. Asseen in FIG. 4, the slot 58 is set in a predetermined angularrelationship which is offset from a line perpendicular to the sides ofthe portion 26 by the angle A. in actual practice, the angle A may befor example approximately 12.

A number of aligned cylindrical openings 60 extend through the bar 22along the length of the machine, and each opening is adapted to closelyreceive the cylindrical shaft 54 of one block 20 as described above. Forthe reasons to become apparent, the lateral dimension of each opening 60(or the thickness of the bar 22) is somewhat greater than that of theshaft 54. A longitudinally extending threaded aperture 62 communicatesat substantially right angles with each of the openings 60, and isdesigned to threadedly receive a socket head capscrew 64 for securingthe shaft 54 in the opening 60 in the manner shown in FIG. 1.

To facilitate establishment and maintenance of the desired angularalignment of the block 20 in relation to the bar 22, the ends of theopenings 60 remote from the bar 22 include a continuous transversechannel 66 communicating with each of the openings 60. An elongated flatkey 68 which may be fabricated from spring steel or other suitablematerial, is adapted to be received in the channel 66 and slot 58 of theshaft 54 as shown in FIG. 1 to preclude rotation of the shaft 54 in theopening 60. Thus by proper placement of the slot 58 on the end 56 of theshaft, the desired angular positioning can be readily obtained. Also,the channel 66 may be indented as shown at 70 after the key 68 is inposition to thereby prevent subsequent withdrawal of the key.

From the above description, it will be apparent that the presentinvention provides a novel structure for mounting the cutting knives 16in the block 20 which includes a clamping bracket 40 adapted to engagethe knives at a pair of spaced contact points and which is easilyoperable by the tightening of a single capscrew. In addition, a simpleand foolproof mounting structure for securing the block 20 to the bar 22in a predetermined angular alignment is provided.

In the drawings and specification, there has been set forth a preferredembodiment of the invention, and although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

lclaim: 1. In a tufting machine for forming a cut pile fabric andincluding means for carrying a yarn through a backing fabric to form aplurality of tufting loops therein, the combination therewith of loopermeans operatively associated with said yarn-carrying means for engagingand retaining the tufting loops,

severing means operatively associated with said looper means andincluding a knife bar mounted for oscillatory movement in relation tosaid looper means, a knife block, means for connecting said knife blockto said bar in a predetermined angular relationship, and a knife carriedby said knife block and adapted to cooperate with said looper means insevering the yarn loop upon relative oscillatory movement between theknife bar and looper means,

said connecting means including a cylindrical shaft having one endconnected to said knife block and terminating in a remote free end, atransverse slot positioned in said free end at a predetermined angle, acylindrical opening extending through said bar and adapted to closelyreceive said cylindrical shaft, a channel in said bar communicating withone end of said cylindrical opening, and a key adapted to be received insaid channel and transverse slot when said shaft is received in saidopening for maintaining said shaft in a predetermined angularrelationship with said bar.

2. The tufting machine as defined in claim 1 wherein said connectingmeans further includes a threaded aperture extending into said bar andcommunicating at substantially right angles with said cylindricalopening, and a locking screw adapted to be threadedly received in saidthreaded aperture and engage the shaft.

3. The tufting machine as defined in claim I wherein said knife blockcomprises a body member having side edge portions and a connecting web,means defining a pair of opposed grooves extending into said side edgeportions and receiving said'knife, means defining a pair of spaced slotsextending laterally into one of said side edge portions and intocommunication with the associated groove, and clamping means forretaining said knife in said grooves and comprising a U-shaped bracketincluding a pair of spaced-apart legs adapted to enter said spaced slotsand engage said knife at spaced points.

4. A knife block for cut pile tufting machine comprising,

a body member having side edge portions and a connecting web, meansdefining a pair of opposed grooves extending into said side edgeportions for mounting a knife therein,

means defining a pair of spaced slots extending laterally into one ofsaid side edge portions and into communication with the associatedgroove, and

clamping means for securing a knife in said opposed grooves andcomprising a bracket including a pair of spaced-apart legs adapted toenter said lateral slots, and means for translating said legs into saidslots such that said legs will engage a knife positioned in said opposedgrooves.

5. A knife block as defined in claim 4 wherein said means fortranslating said legs into said slots comprises a threaded boreextending laterally into said one side edge portion intermediate saidslots, an aperture in said bracket, and a threaded member adapted toextend freely through said bracket aperture and into engagement withsaid threaded aperture.

6. A knife block as defined in claim 5 wherein said bore extendslaterally into said one side edge portion a distance less than thelateral extent of said slots.

7. A knife block as defined in claim 6 further comprising means formounting said block to a tufting machine knife bar in a predeterminedangular relationship and including a laterally extending cylindricalshaft connected to the side edge portion opposite said one side edgeportion and terminating in a remote free end, and means defining atransverse slot in said remote free end at a predetermined angle foraligning said block with said knife bar.

8. A knife block for a cut pile tufting machine comprising,

a body member having side edge portions and a connecting web, said webdefining a pair of oppositely directed planar faces, and said side edgeportions extending transversely beyond each of said faces,

means defining a first pair of opposed grooves lying flush with one ofsaid planar faces and extending into said side edge portions formounting a first knife therein, and means defining a second pair ofopposed grooves lying flush with the other of said planar faces andextending into said side edge portions for mounting a second knifetherein,

means defining a pair of spaced slots extending laterally into one ofsaid side edge portions and into communication with each of theassociated grooves, a threaded bore extending laterally into said oneside edge portion intermediate said slots, and

clamping means for securing a pair of knives in said opposed grooves andcomprising a U-shaped bracket including a pair of spaced-apart legs andan intermediate segment, said intermediate segment including an apertureengagement with said bore whereby said legs may be advanced into saidslots to engage at spaced points a pair of knives positioned in saidopposed grooves.

1. In a tufting machine for forming a cut pile fabric and includingmeans for carrying a yarn through a backing fabric to form a pluralityof tufting loops therein, the combination therewith of looper meansoperatively associated with said yarn-carrying means for engaging andretaining the tufting loops, severing means operatively associated withsaid looper means and including a knife bar mounted for oscillatorymovement in relation to said looper means, a knife block, means forconnecting said knife block to said bar in a predetermined angularrelationship, and a knife carried by said knife block and adapted tocooperate with said looper means in severing the yarn loop upon relativeoscillatory movement between the knife bar and looper means, saidconnecting means including a cylindrical shaft having one end connectedto said knife block and terminating in a remote free end, a transverseslot positioned in said free end at a predetermined angle, a cylindricalopening extending through said bar and adapted to closely receive saidcylindrical shaft, a channel in said bar communicating with one end ofsaid cylindrical opening, and a key adapted to be received in saidchannel and transverse slot when said shaft is received in said openingfor maintaining said shaft in a predetermined angular relationship withsaid bar.
 2. The tufting machine as defined in claim 1 wherein saidconnecting means further includes a threaded aperture extending intosaid bar and communicating at substantially right angles with saidcylindrical opening, and a locking screw adapted to be threadedlyreceived in said threaded aperture and engage the shaft.
 3. The tuftingmachine as defined in claim 1 wherein said knife block comprises a bodymember having side edge portions and a connecting web, means defining apair of opposed grooves extending into said side edge portions andreceiving said knife, means defining a pair of spaced slots extendinglaterally into one of said side edge portions and into communicationwith the associated groove, and clamping means for retaining said knifein said grooves and comprising a U-shaped bracket including a pair ofspaced-apart legs adapted to enter said spaced slots and engage saidknife at spaced points.
 4. A knife block for cut pile tufting machinecomprising, a body member having side edge portions and a connectingweb, means defining a pair of opposed grooves extending into said sideedge portions for mounting a knife therein, means defining a pair ofspaced slots extending laterally into one of said side edge portions andinto communication with the associated groove, and clamping means forsecuring a knife in said opposed grooves and comprising a bracketincluding a pair of spaced-apart legs adapted to enter said lateralslots, and means for translating said legs into said slots such thatsaid legs will engage a knife positioned in said opposed grooves.
 5. Aknife block as defined in claim 4 wherein said means for translatingsaid legs into said slots comprises a threaded bore extending laterallyinto said one side edge portion intermediate said slots, an aperture insaid bracket, and a threaded member adapted to extend freely throughsaid bracket aperture and into engagement with said threaded aperture.6. A knife block as defined in claim 5 wherein said bore extendslaterally into said one Side edge portion a distance less than thelateral extent of said slots.
 7. A knife block as defined in claim 6further comprising means for mounting said block to a tufting machineknife bar in a predetermined angular relationship and including alaterally extending cylindrical shaft connected to the side edge portionopposite said one side edge portion and terminating in a remote freeend, and means defining a transverse slot in said remote free end at apredetermined angle for aligning said block with said knife bar.
 8. Aknife block for a cut pile tufting machine comprising, a body memberhaving side edge portions and a connecting web, said web defining a pairof oppositely directed planar faces, and said side edge portionsextending transversely beyond each of said faces, means defining a firstpair of opposed grooves lying flush with one of said planar faces andextending into said side edge portions for mounting a first knifetherein, and means defining a second pair of opposed grooves lying flushwith the other of said planar faces and extending into said side edgeportions for mounting a second knife therein, means defining a pair ofspaced slots extending laterally into one of said side edge portions andinto communication with each of the associated grooves, a threaded boreextending laterally into said one side edge portion intermediate saidslots, and clamping means for securing a pair of knives in said opposedgrooves and comprising a U-shaped bracket including a pair ofspaced-apart legs and an intermediate segment, said intermediate segmentincluding an aperture and said legs being adapted to enter said spacedslots, and a threaded member adapted to pass freely through saidaperture in said intermediate segment and into threaded engagement withsaid bore whereby said legs may be advanced into said slots to engage atspaced points a pair of knives positioned in said opposed grooves.